Refractory dental mold for casting alloys



1 m lsldplder but A Patented May 27, 1941 UNITED STATES PATENT OFFICE 2,243,094 am-"asc'roar DENTAL mom roa CASTING ALLOYS Cornell Joel Grumman, Millburn, N. J.

No Drawing. Application December 12, 1939, Serial No. 808,829

1 Claim. (CL 22-488) The object of my invention is the production oi Mixture (1) a mold into which dental metals or dental me- Per cent tallic alloys can be cast with a clean nonoxidized Crude zircon san 68 accurate surface, in intricate designs. Crude milled zir n 14 My mold composition consists oi a mixture oi 5 Powdered ball clay 12 zircon and zirconia and entails the use oi zir- Portland cemen 6 o epom' ehs the 0 Water ut 8 me are given ow:

Zircon mixture (by weight) for medium set 10 (30 minutes) Parts Refined zircon granular... 100 Refined zircon milled Calcined magnesium oxide 1. 5 Zirconium oxychioride solution. 14 1.38 sp. gr.

Zircon mixture (by weiaht) for last set (1.5 minutes) 138 sp. gr.

0n the above two methods, aiter mold is made care should be taken not to allow shape to dry oil at any point until set, strip pattern M2531 uniformlyeither at 100 gr 150 '5, Magn um oxide content oi 5 0 causes ediate setting; magnesium oxide content of 4% in conjunction with 13% oi zirconium oxy-chloride; 20% of fine silica and the balance a bond silica or a 20 mesh EH53 mixed in the proportion cl 5 ounces oi the. above mixture to 10 cc. oi water produces a plastic mass which can be vibrated to form a Without departure irom the scope oi this invention any und zirconium silicate can be substitu limitedtoless than 33%. Mai esiyg. M u: may also be substituted in e nding agent in this invention.

Within the scope oi the invention cla r i F result being and this invention.

Other reiractory aezresate can be added in this invention to lessen shrinkage or cost oi properties, ior example chromite.

The features oi novelty of the invention are:

1. Higher reiraotcriness ICOPG 0! dental mold in amost ideal manner. The setting 40 2. The use oi zirconium compound time permitting 10 minutes in which to mix and tom the mold with an immediate set thereaiter.

The zirconium onchloride method ior zirccni mixture (by weight) is: y 7

1.88 specific gravity.

and mixtures of binding-crude and refined m ior reiractory purposes which make the binder 3. The use oi a metallic silicate in a dental investment.

In separate patent applications I will describe the use oi. other metallic silicates ior dental investments.

belt and 1700- Fahrenheit ior hish iusing alloy castings.

Having thus described my invention what I claim is: Acasting mold and mold material ior metallic additions less oostly'are given below. I also give dentures, and the like, comprising zirconium on an auxiliary binder for use with zircon which has given good results. The mixture'in these cases are given by weight.

chloride solution 8 to 15%, magnesium oxide .9

to 2%, balance zircon and zirconia. CORNELL JOELGRQBSMAN.

EXAMlNEl m esium silicate, zirconium schlofia a re-' Tfiiiry aggreaE', or out 4 addition 

